Ford Racing shows how a Mustang Cobra Jet engine is built
Mustangs Daily



As we reported earlier, the production of the 2012 Mustang Cobra Jet is well underway at the Auto Alliance Plant in Flat Rock, Michigan. The engines, however, are built separately at Ford’s Romeo engine assembly plant that has produced more than 10 million V8s for the Mustang, F-150, Explorer and other Ford vehicles. The Mustang Cobra Jet’s engine doesn’t go through the regular assembly line, though, and a dedicated team hand-builds each of the motors on what is called the Romeo Niche line. This special assembly program was started in 1996 to produce engines for special projects like the SVT Cobra and Ford GT, and it added the Cobra Jet engine in 2008.

Ford Racing was kind enough to share what goes into the creation of each engine, and has posted pictures of each step of the build process from the arrival of the engine blocks to the final testing and assembly:

All 2012 Cobra Jet engines start with a 5.4 Liter aluminum block sourced from the Ford Racing catalog (Part # M-6010-GTWS or M-6010-M54A). To begin the build, the block is paired with a crankshaft and run through a high-tech washing machine then quickly dried with a combination of compressed air and vacuum lines.



Ford Racing shows how a Mustang Cobra Jet engine is built



Once washed and dried, the block is fitted with its dedicated carrier mounts that use the engine’s motor mount attachment points. The carrier is used to rotate the work-in-process engine 360-degrees and move the engine from build station to build station.



Ford Racing shows how a Mustang Cobra Jet engine is built

Station One: Block Prep and Crank Install

The main-cap bolts are loosened and the main caps removed so the main bearings and crank can be installed. The Cobra Jet uses a double-keyed steel crank that is similar to the units installed in the 2011 GT500.

Before leaving station one, the main caps are torqued down with a computer controlled torque wrench. Most of the power torque wrenches on the Niche Line are electric, and they’re calibrated by a computer program that ensures the fasteners receive the proper torque.



Ford Racing shows how a Mustang Cobra Jet engine is built


Station Two: Pistons and Connecting Rods

The Cobra Jet forged pistons and piston rings are sourced from Mahle and the H-beam steel connecting rods come from Manley. Each engine has a two person build team that works in tandem on each engine during the build process.



Ford Racing shows how a Mustang Cobra Jet engine is built


For piston installation, one team member uses a piston tool to collapse the rings while the other member uses a guide to direct the connecting rod big-end over the crank throw. Once the piston and rod assembly is aligned, a piston installation tool is used to knock the piston into the bore.

Once seated, the piston cap and rod bolts are installed. When all eight pistons/rods are installed on the crank, the piston cap bolts are torqued with a computerized torque wrench.



Ford Racing shows how a Mustang Cobra Jet engine is built


Station Three: Oil Pump and Seals

After the pistons are in place, the front and rear crank seal and oil pump are installed. The high volume gear driven oil pump is driven off the crank and is sourced from the GT500 parts bin.



Ford Racing shows how a Mustang Cobra Jet engine is built


Station Four: Cylinder Head Prep and Install

With the short block assembled, the Cobra Jet’s DOHC heads are prepped for installation. The heads are similar to the GT500 units but feature Cobra Jet spec cams and valve springs. They arrive at the Niche line build station pre-assembled with cams, springs and roller finger followers already installed. While on the prep table, head bolts are placed in the heads before they are set on the engine.



Ford Racing shows how a Mustang Cobra Jet engine is built


At the head install station, the engine team sets a pair of MLS head gaskets in the engine followed by the left and right cylinder heads. The heads are then torqued in place with a computerized overhead torque gun.



Ford Racing shows how a Mustang Cobra Jet engine is built


Station Five: Timing Set Installation

The timing set arrives pre-kitted from the suppler and includes all gears, chains, guides and tensioners needed to run four cams. The build team member aligns the timing set to the appropriate marks on the chain and tightens the bolts before releasing the tensioners. All tensioner pins are saved with the engine build sheet as a quality control process.



Ford Racing shows how a Mustang Cobra Jet engine is built


Station Six: Front Cover, Cam Covers and Oil Pan

The front engine cover is installed followed by the trademark Ford blue DOHC cam covers.



Ford Racing shows how a Mustang Cobra Jet engine is built


With the front cover and heads sealed, the build team seals up the bottom of the engine with the installation of the oil pump pick-up tube and oil pan with integral windage tray.



Ford Racing shows how a Mustang Cobra Jet engine is built


Station Seven: Balancer and Leak Test

The Cobra Jet engine uses a harmonic balancer from Innovators West, Inc. The billet aluminum unit is SFI approved and legal in NHRA Stock and Super Stock.

Once the engine is sealed, the exhaust ports and intake ports are sealed off and air is pumped into the engine to test for leaks. Once the leak test is passed, the engine is ready for its supercharger installation.



Ford Racing shows how a Mustang Cobra Jet engine is built


Station Eight: Supercharger Install

Base 5.4L Cobra Jet engines are topped off with a 2.3 liter TVS supercharger unit and Super Cobra Jet engines feature a 4.0L Ford Racing/Whipple unit. The superchargers arrive at the NICHE line preassembled in a unit known as the “Charge-Air assembly” with intercooler, fuel injectors and fuel lines already in place.



Ford Racing shows how a Mustang Cobra Jet engine is built


The build team tops the Cobra Jet off with a unique engine wiring harness that adds specific wires for dash mounted Ford Racing gauges and saves weight by eliminating any unnecessary wiring found on a stock GT500 harness.



Ford Racing shows how a Mustang Cobra Jet engine is built


Station Nine: Cold Fire Test

Once the Cobra Jet engine is complete, the build team hoists the engine off the line to a cold test station for a cold test run. The test stand spins the engine up to a predetermined RPM and engine functions like oil pressure and vacuum are monitored. The engine’s flywheel is attached to the stand, the injectors fire, the plugs fire, and the throttle body opens, as if the engine were running. The Aeromotive fuel system is checked for leaks using pressurized air, which shows leaks much easier than fluid would.



Ford Racing shows how a Mustang Cobra Jet engine is built


After passing cold test, the two man team places the Niche line build signature plate. This signature plate has been used since 1996 when the build line started with the SVT program. In the early days of the Niche line, the build team signed the signature plates that were attached to the cam covers. To speed up the process and make a more permanent badge, the signatures are now pressed into the plates prior to installation.



Ford Racing shows how a Mustang Cobra Jet engine is built


Station Ten: Final FEAD Assembly and Packaging

Once the engine passes the cold test, it’s placed back on the moving carrier for final FEAD assembly and crating. At the FEAD installation station, the alternator and A/C eliminator pulley is installed followed by the FEAD drive belt.



Ford Racing shows how a Mustang Cobra Jet engine is built


Once the engine is complete, the assembly is placed in a custom wood crate in preparation for the trip south to Flat Rock Michigan.



Ford Racing shows how a Mustang Cobra Jet engine is built